Warped header help for the newb

[oogs]

I have read most of what I could about intake and exhaust manifolds on this forum. Also read a lot about the debate over headers versus oem exhaust manifolds. I currently have headers on my 78 FJ40. The engine was swapped about 7 years ago and headers were placed. I was new to this at the time and just accepted the installers recommendation to do so. Since, I have maybe put 50 miles on her renovating the 40 about 15 min per week. I am a bit more knowledgable now. Anyway, the bolts (not studs in all but one hole) were not tight and the header flange is warped. With a caliper I have measured the flange to be a bit different in thickness from the intake. Anyway here are my choices as I see it.
1- new header and maybe run into the same problem 2- replacement "matched" intake and exhaust manifold from a FJ60 (may be hard to find) 3- just get an exhaust manifold and have I machined to match my intake (may be hard to find a shop). 4- Double gasket and hog down on a new set of studs.
I assume warped header flanges cannot be machined.
I like option 2 if anyone has one they would like to sell or trade for anything they need.
Help and ideas would be appreciated. I live in northen Virginia.
Thanks in advance.

 

[oogs]

I forgot to mention my engine swap was to a 2f out of an 82 FJ60.

 

[Pighead]

You know what I would do first? I'd order a complete set of the correct (OEM) manifold studs, washers and nuts. Maybe even an OEM gasket, or a fel-pro gasket.
Remove your manifold and header and eyeball them, see if they are noticeably deformed.
All headers need some help with fitment. I had to use an angle-grinder and a dremel on mine many times before they fit pretty well.
Torque down on those manifold nuts until just before you break something.
Or try a Remflex fasket.

 

[77mustard40]

Wow that's a big gap, are you only leaking (exhaust) on NO 1? I'd pull both the header and the intake and take both to the machine shop to see 1) if the header can be corrected and 2) if so, have both surfaces machined flat and to try to match the flange ear depths as close as possible. If you find you can't do this, then pursue one of your other options. Good luck.

 

[oogs]

Thanks pighead. Have you or has anyone"welded up" a warped flange to fill the gap. That seems like an irreversible disaster waiting to happen, but I have heard of it. I though about doing what you said. But with that much of a warp as I have, I was worried I would take too much metal and would end up with a big mismatch with the intake. Thoughts?

 

[oogs]

Wow that's a big gap, are you only leaking (exhaust) on NO 1? I'd pull both the header and the intake and take both to the machine shop to see 1) if the header can be corrected and 2) if so, have both surfaces machined flat and to try to match the flange ear depths as close as possible. If you find you can't do this, then pursue one of your other options. Good luck.

No, the vac leak is all the way along the manifold when I spray carb cleaner. I was cranking on the bolts, but i was scared sh@#less I would strip something. Do machine shops need a special jig to match up the header with the intake? Can you even machine a warped header?

 

[Fast Eddy]

There's a thread around here I've seen lately where someone was making stepped washers to help that issue.

I prefer manifolds myself. You don't really need a machine shop, just someone with a belt sander table. It would be possible to do it with a flat file if they weren't that far off to start with.

 

[Pighead]

Thoughts?

I'm wondering if you have incorrect manifold bolts, or something, preventing it from being torqued down correctly. Like maybe you're bottoming out before you snug it down. But you need to assess that header when it's not on the block...

 

[77mustard40]

I was in the endless vacuum leak loop and it was a combo of machined header and intake, four new studs on the top positions (instead of two), and washers filed on one half to cut the exact measured distance between the two surfaces. Add one Felpro gasket, dry, and everything torqued to spec and I'm fixed.

 

[inkpot]

There's a thread around here I've seen lately where someone was making stepped washers to help that issue.

I prefer manifolds myself. You don't really need a machine shop, just someone with a belt sander table. It would be possible to do it with a flat file if they weren't that far off to start with.

Often the problem is that the intake manifold flange is much thicker than the one on the header. It can be machined down to match, or you can use step washers to fill in the difference. Just take the appropriate sized flat washer and cut it off center so it makes the letter C. Fit it under the top washer that is already on the bolt. This will pull the header flange down tight to the gasket/head. The header should flex this much. It may take a couple of washers to make it thick enough to get it tight. This has been done many, many times. John

 

[oogs]

Thanks for the input everyone. Looks like ill start with taking it apart, assessing the header very closely. If its really bad thaen machine it or just get a hold of a matched manifold set. If its not too bad then some combination of studs, thick gasket, half moon washers and hog on it. Is there an ideal way to go with regard to purchasing studs and a THICK gasket? Whats up with this "copper wire seal" stuff?

 

[DSRTRDR]

we did what inkpot describes when I got my new header